What is the significance of the Torah's description of the Manna to coriander seeds and to crystal?
Rashi and Targum Yonasan: The Manna was (pleasantly) round like a coriander seed and sparkled like crystal.
What is the connection between this Pasuk and the complaints discussed in the previous Pesukim?
Rashi: Wheres the previous Pesukim presents the people's complaint against the Manna, the current Pasuk presents Hashem's answer to the complaint - as it goes on to describe the beautiful appearance of the Manna and its other positive qualities 1 - When it came down it was round (or white), 2 and when it was ready to eat (or when it turned hard), it sparkled like crystal (Targum Yonasan).
Rashbam: It too constitutes a complaint, inasmuch as it describes the physical features of the Manna - hard and dry, rendering it inedible, like dry wheat. 3